TRANSLATIONAL ACTIVITIES OF EF-TU [G222D] WHICH CANNOT BE RECONCILED WITH THE CLASSICAL SCHEME OF THE POLYPEPTIDE-CHAIN ELONGATION CYCLE

We have developed a cell-free system of E. coli that enables us to stu dy the in vitro translation of natural mRNA mediated by wild-type or m utant EF-Tu. Various mutant EF-Tu species have been analyzed, one of w hich, EF-Tu [G222D], appeared to be virtually unable to mediate the tr anslation of natural mRNA. Since this mutant factor is able to partici pate in translation in vivo by suppressing nonsense and frameshift mut ations in cooperation with EF-Tu [A375T], a revision of the generally accepted scheme of the elongation cycle has been proposed (Bosch, L., Vijgenboom, E., & Zeef, L.A.H., 1996, Biochemistry 36). (C) 1996 Acade mic Press, Inc.